externals: allow user to use system lodepng (#7138)

externals/CMakeLists.txt

@@ -327,7 +327,13 @@ if (ENABLE_WEB_SERVICE)
 endif()
 
 # lodepng
-add_subdirectory(lodepng)
+if(USE_SYSTEM_LODEPNG)
+    add_library(lodepng INTERFACE)
+    find_package(lodepng REQUIRED)
+    target_link_libraries(lodepng INTERFACE lodepng::lodepng)
+else()
+    add_subdirectory(lodepng)
+endif()
 
 # (xperia64): Only use libyuv on Android b/c of build issues on Windows and mandatory JPEG
 if(ANDROID)

externals/cmake-modules/CitraHandleSystemLibs.cmake

@@ -21,6 +21,7 @@ option(USE_SYSTEM_ZSTD "Use the system Zstandard library (instead of the bundled
 option(USE_SYSTEM_ENET "Use the system libenet (instead of the bundled one)" OFF)
 option(USE_SYSTEM_CRYPTOPP "Use the system cryptopp (instead of the bundled one)" OFF)
 option(USE_SYSTEM_CUBEB "Use the system cubeb (instead of the bundled one)" OFF)
+option(USE_SYSTEM_LODEPNG "Use the system lodepng (instead of the bundled one)" OFF)
 
 # Qt and MoltenVK are handled separately
 CMAKE_DEPENDENT_OPTION(DISABLE_SYSTEM_SDL2 "Disable system SDL2" OFF "USE_SYSTEM_LIBS" OFF)
@@ -41,6 +42,7 @@ CMAKE_DEPENDENT_OPTION(DISABLE_SYSTEM_ZSTD "Disable system Zstandard" OFF "USE_S
 CMAKE_DEPENDENT_OPTION(DISABLE_SYSTEM_ENET "Disable system libenet" OFF "USE_SYSTEM_LIBS" OFF)
 CMAKE_DEPENDENT_OPTION(DISABLE_SYSTEM_CRYPTOPP "Disable system cryptopp" OFF "USE_SYSTEM_LIBS" OFF)
 CMAKE_DEPENDENT_OPTION(DISABLE_SYSTEM_CUBEB "Disable system cubeb" OFF "USE_SYSTEM_LIBS" OFF)
+CMAKE_DEPENDENT_OPTION(DISABLE_SYSTEM_LODEPNG "Disable system lodepng" OFF "USE_SYSTEM_LIBS" OFF)
 
 set(LIB_VAR_LIST
     SDL2
@@ -61,6 +63,7 @@ set(LIB_VAR_LIST
     ENET
     CRYPTOPP
     CUBEB
+    LODEPNG
     )
 
 # First, check that USE_SYSTEM_XXX is not used with USE_SYSTEM_LIBS

externals/cmake-modules/Findlodepng.cmake

@@ -0,0 +1,31 @@
+if(NOT LODEPNG_FOUND)
+    find_path(LODEPNG_INCLUDE_DIRS NAMES lodepng.h
+            PATHS
+            /usr/include
+            /usr/local/include
+            )
+
+    find_library(LODEPNG_LIBRARY_DIRS NAMES lodepng
+            PATHS
+            /usr/lib
+            /usr/local/lib
+            )
+
+    if(LODEPNG_INCLUDE_DIRS AND LODEPNG_LIBRARY_DIRS)
+        set(LODEPNG_FOUND TRUE CACHE INTERNAL "Found lodepng")
+        message(STATUS "Found lodepng: ${LODEPNG_LIBRARY_DIRS}, ${LODEPNG_INCLUDE_DIRS}")
+    else()
+        set(LODEPNG_FOUND FALSE CACHE INTERNAL "Found lodepng")
+        message(STATUS "Lodepng not found.")
+    endif()
+endif()
+
+if(LODEPNG_FOUND AND NOT TARGET lodepng::lodepng)
+    add_library(lodepng::lodepng UNKNOWN IMPORTED)
+    set_target_properties(lodepng::lodepng PROPERTIES
+        INCLUDE_DIRECTORIES ${LODEPNG_INCLUDE_DIRS}
+        INTERFACE_LINK_LIBRARIES ${LODEPNG_LIBRARY_DIRS}
+        IMPORTED_LOCATION ${LODEPNG_LIBRARY_DIRS}
+        )
+
+endif()